Very(!) slowly booting Fedora CoreOS on intel i9 (Hetzner Box)

Booting Fedora CoreOS on Hetzner EX100 (Dedicated Root Server Hosting - Hetzner Online GmbH) (Intel i9-12900K - 128 GB Memory - 2TB nvme ) does not work.

  • Booting the live iso from an USB stick works perfect
  • Installer from live iso works (installing with no ignition for now)

Reboot, Grub Menu, Black Screen.

Initially it looked like a freeze, but it is only running, very, very, very slow.

After a normal looking (very slow boot) the are some errors, maybe someone can tell me what’s going on here, and what to do about it.



In the version I took the screenshot from, I installed to a usb stick from a live iso to rule out nvme/uefi problems. So the nvmes are just there doing nothing, like in the live iso mode.

What’s different installing to an usb stick and running an live iso from an usb stick?

Any idea for further investigation would help.

Boot finishes after > 40 minutes.

A nice person in #fedora-coreos irc channel dropped me the hint to:
https://docs.fedoraproject.org/en-US/fedora-coreos/emergency-shell/

and thankfully adding the correct “delete-karg” did the trick

coreos-installer:release install /dev/nvme0n1 -s stable -i /data/XXXX.ign --delete-karg ‘console=ttyS0,115200n8’

=> The server now boots just normal at regular speed (fast), inition jus works normal

I just wonder, how diagnose that from that boot output.

For your specific case, I saw references to uart_console_write() in the kernel backtrace in your last screenshot.
I did suggest looking at console setup because I seem to remember that I encountered a similar case in the past.

I don’t know the actual root cause of this, but I think it’s related to the specific hardware setup. Possibly the console filling up its output buffer and then slowing everything else as a result, or something like that.

For reference, this kind of troubles are tracked at remove console=ttyS0 on metal · Issue #567 · coreos/fedora-coreos-tracker · GitHub.